Enum clap::builder::Resettable

pub enum Resettable<T> {
    Value(T),
    Reset,
}

Clearable builder value

This allows a builder function to both accept any value that can Into::into T (like &str into OsStr) as well as None to reset it to the default. This is needed to workaround a limitation where you can’t have a function argument that is impl Into<Option<T>> where T is impl Into<S> accept None as its type is ambiguous.

Example

fn common() -> Command {
    Command::new("cli")
        .arg(Arg::new("input").short('i').long("input"))
}
let mut command = common();
command.mut_arg("input", |arg| arg.short(None));

Variants

Value(T)

Overwrite builder value

Reset

Reset builder value

Trait Implementations

impl<T: Clone> Clone for Resettable<T>

fn clone(&self) -> Resettable<T>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Debug> Debug for Resettable<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T> From<Option<T>> for Resettable<T>

fn from(other: Option<T>) -> Self

Converts to this type from the input type.

impl<T> From<T> for Resettable<T>

fn from(other: T) -> Self

Converts to this type from the input type.

impl<T: Hash> Hash for Resettable<T>

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H) where
    H: Hasher, 

Feeds a slice of this type into the given Hasher.

impl<T> IntoResettable<T> for Resettable<T>

fn into_resettable(self) -> Resettable<T>

Convert to the intended resettable type

impl<T: Ord> Ord for Resettable<T>

fn cmp(&self, other: &Resettable<T>) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self where
    Self: PartialOrd<Self>, 

Restrict a value to a certain interval.

impl<T: PartialEq> PartialEq<Resettable<T>> for Resettable<T>

fn eq(&self, other: &Resettable<T>) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Resettable<T>) -> bool

This method tests for !=.

impl<T: PartialOrd> PartialOrd<Resettable<T>> for Resettable<T>

fn partial_cmp(&self, other: &Resettable<T>) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl<T: Copy> Copy for Resettable<T>

impl<T: Eq> Eq for Resettable<T>

impl<T> StructuralEq for Resettable<T>

impl<T> StructuralPartialEq for Resettable<T>